6 A POPULAR SKETCH OF THE GEOLOGY 



fins, and the orbit of the eye, being perfectly and beautifully mark- 

 ed.* A fine skeleton, also, of the Ichthyosaurus was discovered at 

 Barrow a short time since, and purchased by Mr. Laurance, of Lei- 

 cester, for the Birmingham Philosophical Institution, in the museum 

 of which it now forms the chief ornament, its bones having been very 

 carefully and successfully denuded of their stony envelope.t The 

 beds of limestone are the only parts of the lias which are of any uti- 

 lity ; it forms generally a low uninteresting country, the land being 

 cold and bearing few trees, while the brooks and rivers are slow and 

 sluggish streams. 



New Red Sandstone. 



Beneath the lias lies the new red sandstone formation, the upper 

 beds of which accordingly come out to the light of day where the 

 lowest of the former terminate. In Leicestershire, therefore, the 

 before- mentioned boundary of the lias will form the eastern boundary 

 of that portion of the new red sandstone which appears at the surface. 



The new red sandstone of England consists of 



1. Red marls, with green and white stripes, containing gypsum and 



rock salt, 200 or 300 feet. 



2. Red and white sandstones, with occasional beds of marl and 



conglomerates (masses of pebbles cemented together) 500 

 or 600 feet. 



8. In the northern part of England, magnesian limestone, 200 or 

 300 feet. 



4. Lower red sandstone, about 100 feet, but variable. 



The two latter portions are nowhere seen in Leicestershire, but 

 the upper ones are well and distinctly exhibited. The first or the 

 variegated marls, coming out from beneath the lias, gradually rise to 

 the west till they form a line of low hills parallel with that of the lias 

 before mentioned, and from two to three miles to the west of it. 

 These hills, from the village of Lyston southwards, form an escarp- 

 ment, X overlooking the valley of the Soar. They are, however, fur- 



• For figures and descriptions of fossil fishes I must, ot course, refer the 

 reader to the splendid work of M. Agassiz, now publishing, which ought to 

 have a place in every public library in the kingdom. 



-j- An account of this specimen was lately read to the members of the In- 

 stitution by Dr. Ward, of Birmingham, from which an extract appeared in 

 the last number of The Analyst. 



X An escarpment is the steep side of a range of hills, where the ends, or 



