1884.} Geology and Paleontology. Q21 
tologist but immense numbers of nummulites. Sandstone is the 
chief constituent, but there are thick bands of claystones, flint, 
gypsum, etc. -The total thickness cannot be less than 400 meters. 
This formation is the most important factor in the mountains of 
the Tell, and a multitude of summits are composed of the sand- 
stones and nummulitic limestones. It is superposed on various 
formations, and is usually highly unconformable with the stratum 
on which it rests. The eocene appears in two interrupted belts par- 
allel to the coast, one in the Tell, the second in the north of the 
high plateaux. It does not occur iñ the south, and is more de- 
veloped in the east than in the west. The miocene,.on. the 
contrary, is most developed in the west, and, though frequently 
composed of rocks very similar to the eocene, can usually 
distinguished by its highly fossiliferous character. In the depart- 
ment of Constantine part of the deposits are lacustrine or fluvia- 
tile. Miocene strata occupy large areas in the Tell, apparently 
filling depressions produced after the deposit of the eocene, and 
in the province of Oran they reach their highest development, 
and are rich in fossil echini. 
The area occupied by the pliocene is much more limited, and 
is composed of some isolated lacustrine deposits in the province 
of Constantine, with perhaps certain belts in the Saharian region, 
and of small enclosed patches of marine origin filling depressions 
near the coast.. The quaternary covers enormous areas, and be- 
longs to different epochs. The strata are terraced in the valleys 
hollowed out during the quaternary period, or fill the great de- 
Pressions of the high plateaux and of the Sahara. These are of 
lacustrine, fluviatile or continental origin, but marine beds occur 
in many spots along the coast from Tripoli to Morocco. The 
great superficial development of these beds in the plateaux and 
the Sahara, and the thickness they attain in the depressions, cause 
Some to refer them to the upper tertiary, and some to believe them 
to be the work of a gradually drying-up interior sea. Several of 
the characteristic mammals have been found, but it cannot be 
Said that these beds have been thoroughly explored. 
k Tue Carsonrrerous Frora oF Ruope Istanp.—The following 
is a list, with descriptions of two new species, of such of the fossil 
tboniferous plants of Rhode Island as are contained in the 
useum of Brown University, Providence, R. I., and which have 
€n sent me for identification, and of those which I have had 
Opportunities to see in different collections, especially that of the 
Museum of Comp. Zoöl. of Cambridge, and of Mr. R. D. Lacoe 
Pittston. Those from Valley Falls, R. I., have in part been 
collected by Mr. Thomas Battey, and those from Rhode Island, 
near Portsmouth, were. collected by J. H. Clarke, Esq. A few 
Species have been collected at Cranston, R. IL, by Professor A. S. 
Packard, 
