568 Geological Socicfi/; — Prof. Agassiz on Glaciers, 



mulabllis, and A. coronatvs. M. Roemer has noticed the Hils clay 

 near Hildesheim, near Celfeld, where it contains a considerable 

 layer of iron ; at the foot of the Deister near Hanover, and near 

 Trenndorf. 



i. Weald clay. — A stiff" bluish or brownish clay, seldom contain- 

 ing subordinate beds of limestone and sandstone. The fossils are 

 almost exclusively the same as those enumerated in Dr. Fitton's 

 memoir on the beds below the chalk in the south-east of England ; 

 and are entirely freshwater, with the exception of an Astarte. 



k. Hastings sandstone. — In the north of Germany this formation 

 is composed of a white, grey or fawn-coloured sandstone, sometimes 

 alternating in the upper part with greyish clay, and contains from 

 seven to ten beds of coal. Its general thickness amounts to 500 or 

 800 feet. The beds of coal vary from one to three feet in thickness, 

 and are separated by sandstone, which is sometimes only a few feet 

 thick. The fossils belong to the genera Paludlna, Unio, Endoge- 

 nites, Abies, Sphenopteris, and Lonchopteris , and M. Roemer has 

 found every species mentioned in Dr. Fitton's memoir before al- 

 luded to. The sandstone is generally less ferruginous than in 

 England. 



I. Purbcck strata. — These beds are described by M. Roemer as 

 consisting of shelly limestones alternating with thin layers of sand- 

 stone, and concretional masses of grit. He has observed two dirt- 

 beds, but as j'et no Cycadeoidea. The shells which he has found, 

 are partly marine, partly freshwater, and belong to the genera 

 Paludina, Ostrea, Cyrena, Gervilia, Serpula, &c. 



m. Portland stone. 



The Wealden formation, M. Roemer states, is exhibited near 

 Helmsted. He hopes it will be exposed near Hildesheim. More 

 westward it extends from Hanover by Minden, to Iburg and Rheine 

 near Munster in Westphalia ; furnishing almost everywhere a very 

 good coal. The fossils found in the strata below the lower green- 

 sand, M. Roemer has accurately figured and described in his works ; 

 and they proved the identity of the Wealden deposits of England 

 and the north of Germany. 



A letter from H. B. Mackeson, Esq. to Dr. Fitton, dated Hythe, 

 June 7th, 1840. 



On the 19th of Ma3% Mr. Mackeson discovered some portions of 

 a large saurian, he believes an Iguanodon, near the bottom of the 

 lower greensand in the vicinity of Hythe. On the 6th of June, 

 he revisited the quarry, and ascertained that the work-people had 

 followed the remains for upwards of fifteen feet. On that occasion, 

 Mr. Mackeson superintended the disinterment of probably a tibia. 

 This bone, and others previously obtained, with their bulky matrix, 

 required a cart and two horses for their removal. Up to the date 

 of the letter, no vertebrae, teeth, phalangeal or smaller bones of the 

 extremities had been found by the workmen. In the same quarry, 

 Mr. Mackeson has obtained a large Ammonite, Gervillia aviculoides, 

 and other shells characteristic of the lower greensand. 



