740 
down the river. At Stony Bluff, on the borders of Scriven county, the 
calcareous deposit is no longer visible, the cliff being composed of 
siliceous beds of the burr-stone and millstone series, resting upon 
brick-red and vermilion-coloured loam. This section, Mr. Lyell states, 
is of great importance, as it concurs in proving that the millstone of 
this region, with its eocene fossils, is an integral part of the great red 
loam and sand formation usually devoid of organic remains. The 
burr-rock of Stony Bluff abounds with cavities and geodes partially 
filled with crystals of quartz and agates. In the fragments scattered 
over the adjacent. fields Mr. Lyell observed casts of univalves. At 
Millhaven, eight miles from Stony Bluff and five from the Savannah 
river, these siliceous beds again crop out and afford casts of the genera 
Pecten, Eulima or Bonellia, and a Cidaris. It had been pierced 
through to the depth of twenty-six feet, and was associated with red 
loam, yeaa sand and kaolin, affording further evidence of these de- 
posits belonging to one formation. 
One mile west of Jacksonborough, in the ford of Briar and Beaver 
Dam Creeks, is a limestone passing upwards into white marl which 
appears to have been deeply denudated, and is overlaid by sand that 
belongs to a formation of sand, loam, and ferruginous sand-rock, re- 
ferred by Mr. Lyell to the red loam and burr-stone series. The 
limestone and marl, although rarely exposed in sections, are consi- 
dered to constitute very generally the fundamental strata of the re- 
gion on account of the not unfrequent occurrence of lime-sinks or 
circular depressions, formed in the beds of loam and sand by subter- 
ranean drainage. The fossils procured from the limestone of Jack- 
sonborough by Mr. Lyell, as well as those presented to him by Col. 
Jones of Millhaven, were for the greater part well-defined casts, and 
were specifically new to American paleontologists ; nevertheless he 
has no hesitation, from their general aspect, to regard them as belong- 
ing to the eocene period. The genera enumerated in the paper 
are, Conus, Oliva, Bulla, Voluta, Buccinum, Fusus, Cerithium ?, 
Trochus, Calyptrea, Dentalium, Crassatella, Chama, Cardium, Cy- 
therea, Lithodomus, Lucina, Pecten, and Ostrea. The Trochus is 
considered identical with the T. agglutinans which occurs in the Paris 
basin ; and the Lithodomus to be undistinguishable from the L. dac- 
tylus of the West Indies, one of the few eocene Parisian fossils iden- 
tified by Deshayes. 
All the Bluffs examined by Mr. Lyell on the Savannah river below 
Briar Creek belong to the beds above the limestone, and are refer- 
able chiefly, if not entirely, to the burr-stone formation. In white 
clays exposed a few hundred yards below Tiger Leap in Hudson’s 
Reach, the author found impressions of Mactra, Pecten and Cardita, 
also fragments of fishes’ teeth, particularly of the genus Myliobates, 
likewise several teeth of the genus Lamna, and one belonging to a 
Notidamus or a nearly allied genus. At Sisters Ferry he observed 
not only the brick-red loam, with the red and grey clay and sand, 
but a highly siliceous clay, which though soft when moist, exhibits a 
conchoidal fracture when dry, and resembles flint ; in some spots the 
clay also passes into a kind of menilite. 
