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The rocks around the hot springs of Peer Mugger, ten miles east of Kurrachee, consist of nummulitic limestone, in some cases highly crystallised, and where the fossils, according to Captain Ficary, occasionally are entirely altered. Two miles further to the westward, occurs the group of Minora Hills, about 800 feet above the sea, and 500 above the plain around. On the eastern side a crater has been blown out; the ruins are scattered around. It is oval in form, about The explosion has burst

150 feet in length, and 50 across. away one of the sides, and blown through the strata adjoining. It seems as if a vast deluge of water had for a short time been discharged from it. There is no tradition* in existence regarding it, nor is anything known of the date when it was last in commotion. It has clearly been subject to the great changes which have taken place around, and it is probable it preceded the deposit of post-pleocene clays found at its base, as these bear no appearance of disturbance, and have most likely been deposited by the sea, subsequent to the explosion. There are several other craters of lesser size, and more imperfect structure round Minora. The rocks at the Lukkee Pass hot springs appear to be of exactly the same description as those at Peer Muggun-their position in all likelihood due to volcanic influence of comparatively recent existence. The hot springs of Peer Muggun attain a temperature of from 100 to 150, and yield a very copious discharge the water is perfectly pure, and fertilizes the

* Captain Carless, who gives (1838) by far the best account of this district yet published, speaks of "a celebrated hill called Jibel Pubb, 20 miles northwest of the hot springs, of which wonderful stories are related all over the country;" but he does not tell us what these stories are. Bombay Geographical Transactions,

† Captain Ficary describes the clays as post-pleocene. He makes no mention of the crater. I visited it, and took careful drawings and measurements of it in March 1850. The highly-crystalline state of the rock is conspicuous. I confess I could discover no evidence of any diminution of its fossils around the springs or near the crater. The rocks which every where around are one mass of shell and zoophytes, the corals being often in the most beautifully perfect state that can be imagined, have been in some places highly crystallised, the organic remains being in part obliterated. The crystals are occasionally arranged in beautiful star-like forms, like many members of the zoolite family.

soil around.* One of the tanks contains nearly 200 crocodiles. There is a spring at no great distance which affords large deposits of sea salt.

The next volcanic group to be met with in this direction is that of Hinglay, a series of mud volcanoes very similar in point of form to those of Cheduba, along the sea-board of Lus, and now in great activity. Here there is no appearance whatever of there ever having been any eruption of lava. The first of these are called the Koops of Chimdra ; they are believed to be of Divine origin, and to be possessed of miraculous virtues.

The extent of this volcanic field has never been precisely determined; it extends some fifty or sixty miles inward, and at least three times as much along-shore.

The band, if band it be, now trends away southerly from lat. 22° to lat. 12°; and next group we meet in with is that at the mouth and lower part of the Red Sea, commencing with Cape Aden,† and concluding with Gibbel Teir, extending across from the former of these to the Salt Lake Assal, inland from Tadjoura-so inland for 100 miles.

Aden is spoken of by Arab writers as having been in a state of activity within the historic period; and though there scarcely seems evidence sufficient of this to be relied on, and a considerable presumption to the contrary, it has all the appearance of great recency.

(To be concluded in our next Number.)

E

The hot spring takes its name from Peer Muggun, a Mohammedan saint whose shrine is close by. The coincidence of the sound with the designation given to the long-snouted crocodile (muggun) had led to the inference that it was Peer Muggun, the Crocodile saint. The crocodiles in the tank are of the kind called Gavial-they are precisely similar to those of the Nile and Ganges -not at all like the muggun.

† See Dr Bird's Notes to Captain Foster's Account of Cape Aden, Bombay Geographical Transactions. Referred to in Report of the Society for 1850,

vol. ix.

On Reptilian Remains found in the Old Red Sandstone of

Morayshire.

1. Notice of the Discovery of Reptilian Foot-tracks and Remains in the Old Red Sandstone of Morayshire. By Captain LAMBERT BRICKENDEN, F.G.S.

On the coast of Morayshire, between the villages of Covesea and Burghead, strata of crystalline sandstone occur in great thickness, and are regarded as belonging to the upper division of the Old Red or Devonian formation of Scotland. The only fossil discovered in this rock was the imprint of a mass of scales or scutes of a remarkable ganoid fish, named Stagonolepis, by M. Agassiz, until 1850, when the author observed on a block of sandstone, in a quarry at Cummingstone, a distinct series of quadrupedal footprints, traced in an uninterrupted succession across the slab. The imprints are thirtyfour in number, and the track of the right feet alternates with that of the left. These impressions have a rounded form, and are identical with those which are generally regarded as chelonian footprints by palæontologists. In October 1851, from a quarry of sandstone at Spynie Hill, Mr Patrick Duff, of Elgin, obtained a beautiful imprint of the skeleton of a four-footed reptile, about five or six inches in length, and which that gentleman allowed the author to transmit to Dr Mantell to describe, as an appendix to the present communication. The author states that, on finding the chelonian foot-tracks in rocks of an age in which no traces of the class Reptilia had previously been discovered, a strict investigation took place as to whether the sandstone strata, from which the slab was taken, are unquestionably referable to the Devonian formation, to which they had always been supposed, by Mr Hugh Miller and other competent observers, to belong. The discovery of the reptile at Spynie dispelled all doubt on this point; for the beds of Cummingstone and Spynie are identical, and, at the latter place, are capped by the cherty limestone peculiar to the upper division of the old red of the district. The Stagonolepis, found in the same rocks, is emphatically an old red sandstone family of fishes, and confirms the above inferences. The author concludes

with the remark that, by the discovery of the chelonian footsteps and the reptile of Spynie, we have thus for the first time obtained unquestionable evidence that two orders of the class Reptilia existed during the Devonian epoch.

2. On the Telerpeton Elginense, a Fossil Reptile discovered in the Old Red Sandstone of Moray. By Mr PATRICK DUFF; and on supposed Fossil Ova of Batrachians in the lower Devonian Shales of Forfarshire. By Dr MANTELL, LL.D., F.R.S., &c.

The reptile from Spynie, referred to by Captain Brickenden in the foregoing paper, consists of the impression of the skeleton in a VOL. LII. NO. CIV.-APRIL 1852.

354 Reptilian Remains in Old Red Sandstone of Morayshire.

block of sandstone, which is broken into three pieces. The cranium is but obscurely seen. Of the rest of the skeleton scarcely an atom of the osseous substance remains. The impression of the spinal column from the occiput to the pelvis, consisting of twenty-four vertebræ, each supporting a pair of slender ribs, of the left humerus, radius, and ulna, of the femoral and leg bones, of the pelvis, and of a considerable portion of the caudal series of vertebræ, serve to convey a general idea of the form and structure of the original, The author gave a description of its anatomical characters, so far as they can be ascertained from the imperfect state of the specimen, and the result of a comparison with recent forms. He specifies certain osteological characters which are Lacertian, and others that are Batrachian, and he concludes that the original was a peculiar type, which, in the present state of our knowledge, it would be rash to pronounce to belong to either order; and he distinguishes it by a name simply expressive of its high antiquity-Telerpeton (nλs gero), with the specific term Elginense, to denote the locality in which it was discovered. The original was an air-breathing, oviparous quadruped, probably resembling in appearance an aquatic salamander, but with longer limbs and a wider dorsal region than our Tritons, and capable of rapid progression on land and in the water. In connection with the above discoveries, the author states that the Devonian shales of Forfarshire abound with clusters of small, round, carbonaceous bodies, which are commonly associated with aquatic plants. These fossils have been figured and described as being probably ova of gasteropodous molluscs, although neither shells nor casts of shells of any kind have been found in the strata. The discovery of reptiles in the upper member of the Old Red of Scotland led Dr Mantell to recur to an idea he formerly entertained, that the Forfarshire fossils were the spawn of Batrachians of the family Ranidæ; and upon comparing them with a mass of carbonized recent frogs' eggs, the resemblance was found to be so complete as to induce him to conclude that the fossil eggs are referable to reptiles and not to molluscs. In conclusion, the author dwells on the importance of the researches of Captain Brickenden and Mr Duff in a paleontological point of view; for they establish the existence during the Devonian or Old Red epoch of several orders of a higher class of vertebrate animals than had previously been discovered; while the occurrence of Batrachian ova with aquatic plants, associated with remains of ganoid fishes, which, for aught that is known to the contrary, may have been inhabitants of fresh water, like the existing Lepidostei, together with the entire absence of marine organisms, suggests the probability that the Devonian strata thus characterised, may be of fluviatile origin.

The Silurian System.

As we have inserted in this number of the Edinburgh New Philosophical Journal a short account of Professor Sedgwick's view of the Older Palæozoic Rocks of Great Britain, but chiefly those of the Cambrian System, we think it proper to give a place to the following letter, addressed by Sir R. Murchison to the Literary Gazette of the present date, on the Silurian System :

As the abstract of a memoir by Professor Sedgwick on the Palæozoic rocks, which appeared in your journal of the 6th, might lead some of your readers to suppose that the Silurian system is a baseless fabric which requires reconstruction, I beg permission to state the substance of the reply which I made viva voce at the rooms of the Geological Society, to the points advanced by my old friend, who has become an antagonist-the only one, however, I am acquainted with to views which are, I trust, firmly established.

Divested of numerous local names, the proposition now brought forward (seventeen years after the promulgation of the Silurian nomenclature)* is, that a very large portion of the lower Silurian rocks described by me as the Llandeilo' formation, be transferred to the so-called Cambrian rocks.' 6 On my part, I contend that geologists must adhere to my nomenclature, founded on data which have proved to be true-a nomenclature that has been generally adopted at home and abroad.

The few arguments required to sustain this position will be intelligible to every one. Let those who wish to comprehend what the Silurian system is considered to be by leading geologists, repair to the great and instructive geological museum in Jermyn Street. There they will see that all the inferior slates and limestones of North Wales which contain fossils are named Lower Silurian. They will also see that in the coloured maps and sections illustrative of North Wales, Lower Silurian rocks are represented to extend nearly all over that region; the only strata to which the term Cambrian is applied, being certain masses of unfossiliferous grey wacke, which, like my Longmynd in Shropshire, rise from beneath the lowest fossil-bearing rocks. Why, then, did Sir Henry De la Beche, and his followers in the field, Ramsay, Aveline, Selwyn, and others, adopt this classification? and why has it been confirmed by Edward Forbes, Phillips, Salter, and the paleontologists of the Survey ? Simply, that after a long and careful scrutiny these observers have

*See Philosophical Magazine, 1835, with table, &c. The large work really followed in 1838 (date of Preface), though 1839 is on the title page.

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