THE GEOLOGIST. 
Professor Pictet has lately recognised among the fossils picked up 
at St. Croix, in the Metabief Limouite, a well-preserved spine of the 
Asteracanthiis granulosus, Eger., a fish found by Mantell in the middle 
division of the Tilgate beds. It is interesting to add that Campiche, 
Pictet, and some other Jurassian geologists, have found in the same 
Metabief Limonite numerous vertebrae, teeth, and scales of Plesiosaurus, 
Crocodiles, and fishes, indicating that a rich fauna of vertebrated 
animals existed there during the deposits of the Metabief beds (see 
Description des fossiles du Terrain cretace de Sainte Croix, par Pictet 
et Campiche. Geneve, 1858). If we remark that the middle division 
of the Tilgate beds is precisely where Dr. Mantell found such 
numerous remains of Plesiosauri, Crocodiles, Iguanodons, fishes, &c. ; 
it is not improbable that we may synchi-onize the Lower Neocomian 
with the Lower part of the Hastings Sands, from the Middle division 
of the Tilgate beds downwards, with some degree of truth. I have 
indicated this supposed synchronism by dotted lines. (See PI. I. Abstract 
sections, &c.) 
We have as yet no palseontological evidence that will permit us to 
identify the Middle and Upper Neocomian with the upper part of the 
Hastings Sands and the Weald Clay ; but, if the preceding synchronisms 
be exact, we may accept this also on stratigraphical gi'ounds. 
At all events, it appears from the' preceding remarks, — 1st, that 
the Neocomian is not the equivalent of the Lower Greensand ; 
2d, that the Purbeck beds are coeval with the marine deposits called, 
in the Jura, Salins Limestone ; 3d, that there is great reason to 
suppose that the Neocomian of the Jura is the marine equivalent of 
the Wealden of Kent, Surrey, and Sussex ; and that the great gap 
existing in Great Britain in the marine deposits between the strata of 
Portland and those of the Lower Greensand will be filled up by the 
Neocomian and the Salins Limestone of the Jura Mountains. 
