6 
2.—Uprer Keniry Beps: Chalk with bands of flint. Zone 
with Micraster cor-anguinum in the upper part and Ananchytes ovata 
and Spondylus spinosus below. 
3.—Lower Kentzy Breps: Chalk with fewer flints (dispersed). 
Zone with Holaster planus and Micraster cor-bovis. Whiteleaf 
Beds: Chalk with bands of marl and very few flints. Zone with 
Inoceramus Brongniarti and Galerites albogalerus, about 75 feet. 
4.—Uprer Marpen Park Beps: Chalk without flints, but 
with layers of marl. Zone of Ammonites peramplus and Inoceramus 
mytiloides. 
5.—Lower Marpen Park Beps: Chalk marl and grey chalk. 
Zone of Ammonites varians and Belemnitella plena. Estimated 
thickness of last two beds about 190 feet. 
The Chalk is of marine origin, and indicative of a rather deep 
sea, and of a warmer period than obtains at present in our area. 
The old Cretaceous sea was of great extent, occupying a fair area 
in England, it can be traced by its organisms over a considerable 
portion of Europe, extending about 1,100 miles from east to west and 
840 miles from north to south. Cretaceous beds occur, in some parts 
of India, within 10 or 12 degrees of the equator ; along the eastern, 
southern borders, and part of the western territories of the United 
States ; also in South America, where, along the Chilian Andes, beds 
of this age are now elevated 14,000 feet, as they are also in the Rocky 
mountains to the extent of 6,000 feet above-the sea level ; while, in 
our area, the chalk at Ingpen reaches only 1,100 feet above thesea, 
showing the movements which have taken place since the formation 
of the chalk. I need not, I am sure, describe here those minute 
forms which constitute a large portion of the chalk, as they have, 
doubtless, been objects of frequent examination by the members of 
the Croydon Microscopical Club ; but those who are not so con- 
versant, may be informed that they belong to the lowest division 
of the animal kingdom, the Protozoa, which includes besides 
them the sponges, infusorial animalcules, and some other forms. 
But this contribution of minute life in building up the present 
solid chalk, is of further interest when compared with the accumu- 
lations now taking place over a considerable portion of the Atlantic ; 
for as many of you must be aware, owing to the researches of Dr. 
W. B. Carpenter and Professor W. Thompson, and the still earlier 
investigations of Professors Ehrenberg and Bailey, that accumulations 
are now taking place in its depth of nearly the same nature as the 
* Hence, the whole rise since the Cretaceous period, about the central region of the 
Rocky Mountains, has amounted to nearly 7,000 feet, and from this it decreased eastward 
towards the Mississippi and westward towards the Pacific.—DANA, Manual of Geology, 
p, 504, 
The Cretaceous formation has a thickness in New Jersey of 400 to 500 feet; in 
Alabama 500 to 600; in Texas (including compact limestones with chert) about 800; and 
in the region of the Upper Missouri of 2,000 to 2,500 feet. Cretaceous rocks have been 
found on tue Pacific coast at Vancouver’s Island, at various points in the Coast range in 
California, and along the Sierra Nevada,—DAN4, wbid., p. 468. 
