370 



TPIE GEOLOGIST. 



will confirra the truth of this assertion, and at the same time aftbrcl 

 encouragement to the beginner to go on his way rejoicing, while he 

 scrambles over rugged rocks, and finds himself lost for awhile amidst 

 the changes and contortions which the strata in mountainous regions so 

 frequently undergo. This, we need not say, does not apply to the Lias ; for 

 except in the Alps and a few other similar places abroad, this formation 

 has undergone but little disturbance ; and that portion of it in Glou- 

 cestershire now to be described scarcely rises into hills, and has been 

 subject to little or no alteration in its internal structure since its original 

 deposition. 



We have already described the Upper Lias, the marlstone, and the 

 beds more immediately below ; and we have seen that they each contain 

 a certain number of peculiar fossils, marking distinct stages of life ; 

 and the same remark applies with equal force to the lower and succeed- 

 ing divisions. Owing unfortunately to the paucity of sections, many 

 of these are very rarely exposed in the district — never in one consecutive 

 section — and are chiefly to be observed in the few clay-pits where 

 bricks are made around the town of Cheltenham. At the foot of 

 Eattledown Hill, there is a stratum of yellow clay, about four feet 

 thick, enclosing ferruginous nodules, in which a variety of shells have 

 been met with, viz., BeJemnites eJongatus, Troclms imlricattis, a species 

 of Gervillia, Cardinia attenuata, Modiola cuneata, Spirifer ])unctatus, 

 Area gracilis, A. BucTcani, A. truncata, Jiicula in e qui rah is, and some 

 others, a portion of which are not recognized elsewhere. Unfortunately 

 the pit is now only worked in the lower clays, so that the more peculiar 

 fossils of the yellow clay cannot be obtained. The former are best 

 exposed in a brick pit on the left hand, nearer Cheltenham, and these 

 laminated strata of blue clay are the commencement of the Lower Lias 

 Shale. It is characterised by Ammonites Henlctji, A. Conyheari, A. 

 crcnata, and others, with Perna ventricosa. Below this, the four fol- 

 lowing beds occur, which are each distinguished by the prevalence of 

 certain fossils, met with in greater or less abundance. Thus, according 

 to Professor Euckman, we have the Belemnite-bed," twelve feet 

 <hick, which is succeeded by another yellowish clay, charged with 

 many species of Ammonites, and not exceeding three feet in thick- 

 ness; then strata of dark shale, ten feet thick, marked by a great 

 abundance of a peculiar chel], the mpjwjjodium-'' pondcrosum, many 

 So called from its resemblance to a horse's hoof. It appears to he allied to 

 nir'T. f;;n'dita, and holonos to the same family as Cardinia, another 



n'-mudant and still more characteristic Liassic form.— P. B. B. 



