880 



THE aEOLOGIST. 



The "Black Greys" (border) is one of the most remarkable of 

 the whole series of beds displayed in the Iguanodon quarry. Its 

 sandy border contains an immense accumulation of organic remains 

 — all marine, with the exception of fragments of wood perforated by 

 teredines, of which animals, in most cases, the sheaths remain. The 

 sandstone is of a dark grey, hard and coarse in texture, and about 

 twelve inches thick. A portion is full of the casts and markings of 

 Siphonise and Fucus Targonii. Casts of Trigonia cdcdformis are very 

 abundant, and, as in the Molluskite layer, the shells are open, and 

 of the dead mollusksthe carbonaceous matter is found in large quan- 

 tities. At the junction of the hassock with the limestone beneath 

 it, two beds containing shells in great profusion. The first contains 

 chiefly the shells of a Fanopea, but the substance of the shell is now 

 nothing more than a slight film of lime, v/hich falls to dust when dry. 

 The difficulty of getting specimens is also greatly increased by their 

 crushed condition, being almost flattened by the pressure they have 

 undergone. Immediately under this vein of shells, and sometimxes 

 mingling with them, is seen for the first time a bed of the charac- 

 teristic Gryph^a, or Esogyra. These shells often occur in groups of 

 considerable numbers, and I have had five good specimens within a 

 thickness of stone not exceeding three inches. This bed of shells 

 appears to have only existed for a short period, as the occurrence of 

 an individual in any part of the remaining portion of the layer is 

 rarely seen ; and. indeed, the stone is remarkably free from any re- 

 mains of animal life. The accummlation of Siphonise gives the rough 

 fracture so generally found in ragstone, but occasionally a smooth 

 flat surface is obtained by cleavage. The hassock contains many 

 nodules of clear blue limestone, very similar to septaria. This oc- 

 currence in the coarse sandstone is remarkable, as the stone is of a 

 very clear structure, light blue in colour, and in some instances of a 

 pear-shaped figure, from which I attribute their origin to zoophytic 

 structure, although no traces of such structure has been detected. 



Below the last-mentioned layer the stone is of inferior quality. The 

 fossils are of the same kind as those occurring in the border of the 

 " Black Greys." The only opportunity I have had of examining 

 them was during the sinking of a well, when water was found at 

 twelve feet below the "Black Greys." Detached spiculse, Trigonise, 

 Plagiostomss, stems of Siphonise, Piicatulse, and Belemnites, were 

 very abundant. Tlie layers were as under: — 



Concrctiouary masses of greyisli limestone, from 6 to ] 2 inches in thickness. 

 Few fossils. 



Hard coai'se hassock, 2 feet. in thickness. Siphonise in lai-ge masses ; casts of 



^V-. /<',//',,' (ihcformis. 

 Tliiii l;iyrr of stone. 



Soil ha-Mirk, about 6 inches, -with spiculje. 



On y-l)luc limestone of clear fractnre. Few shells. 6 to 7 inches thick. 

 Hard hassock, 18 inches. Impressions of Siphonise. 



"Water was then found in loose rubbly layers of stone. 



Having now terminated the description of the series found in my 



