412 General Notes. [April, 
beds with the Triassic rests solely upon their position below the 
Jurassic, and has no palzontological proof. Most of the horizons 
of the Jurassic are represented, but organic remains are rare, and 
the strata are sometimes metamorphic. The oldest Jurassic strata 
exist in the mountain region, and are marked by characteristic 
species. The Upper Jurassic (coradlien) appears to form a long 
band running from east-north-east to south-south-west across the 
high plateaus. The Neocomian, or Lower Cretaceous, is met with 
in the Tell, or mountain region, in the high plateaus, and as far as 
the confines of the Sahara, yet does not occupy large areas. The 
Urgo-Aptien (as our authority styles the strata between the Neo- 
comian and the Gault), occupies large areas in the south of the 
country. The Gault (A/dien) acquires in Algiers a thickness of 
150 to 300 meters, and is in great part composed of rocks 
posited mechanically.. It presents distinct characters in different 
parts, and is tolerably rich in fossils. The Cenomanian Is one of 
the most important and widely spread formations of Algiers, 
reaches a thickness of 500 meters, and enters into the formation 
of almost all the mountain masses, except those of the coast. 
Wherever this formation extends the surface of the country ® 
particularly uneven, full of ravines and peaks, or rocky aang 
difficult ascent, and almost completely sterile. These strata 
extremely rich in fossils. Though the Cenomanian occurs re 
north, its greatest development is in the parallel chains | 
- separate the long depression of the chotts from the : a , 
The Turonian is also extensive. It is composed of a com : 
able mass of limestone with Rudistes, and of some other l 
tween this and the Cenomanian. It occurs in the 
tones, ee and l 
black, and the fossils consist to a large extent of ga inp ] 
lamellibranchs, especially oysters, and echini. In ge ee e 
of this stage neither sandstone, sand, dolomite, kot: ed ina 
sponges, polyzoa and brachiopods are entirely y? ee 
are very rare, and cephalopoda represented by 
principally of Ceratites. 
URES. 
mobranchi of the Coal Measures, and I haw re 
ring also in the Permian. Mr. S. Garman 1as Mi 
an account of a shark supposed to have been 
