874 REPORT OP NATIONAL MUSEUM, 1897. 



silica, of cryptocrystalline structure, made in a bed or layer of soft 

 chalk in the form of nodules. But it is not necessary, in order to be 

 flint, that it be in tlie form of nodules nor that they be deposited in 

 chalk; for the tlint of Europe has been found in hard limestone in both 

 nodules and str.ita. That found in the Jura Alps is deposited in strata 

 in hard limestone and not in clialk. That at Spiennes was de])osited in 

 the clay both in strata and nodules. That used in the Mentone caves, 

 of which there were wagon loads, and that along the Riviera, is in 

 nodules and in limestone. Tlie Hint mine at Mur de-Barrez (Aveyron) 

 (fig. 54), opened by MM. Oartailhac and Boule, and the mine at Meudon 

 (Oise) (fig. 56), discovered by Cuvier in 1822, confirms this view. These 

 and other deposits, representing widely separated districts in France 

 and others throughout Europe, show a general condition of flint depos- 

 ited in strata as well as in nodules, and in limestone and clay as well 

 as in chalk. These iieculiarities of formation are paralleled in many 

 localities of the United States. The differences in the deposit, and 

 consequently in the formation of flint, are shown in many places 

 throughout Europe. Some of them have been described, audit it was 

 necessary many other localities could be mentioned. 



The same is true of flint in the United States, whether it be fine 

 under the name of chalcedony, or coarse under the names of chert and 

 hornstone. James D. Dana says:' 



Flint occurs in nodules iu chalk: not nnfreqneutly the nodules are in part ohal- 

 cedonic. Hornstone differs from flint in heing more brittle; it is often found in 

 limestone. Chert is an impure hornstone. Limestones containing hornstone or 

 chert are often called iherty limestones. 



Flint Ridge, Ohio (Plate 13) is a locality noted for its ledge deposit 

 of flint, while the flint disks from Ohio and Illinois (Plates 02,63) show 

 deposits to have been in nodules. Flint disks of the same general 

 shape and of corresponding material have been found iu several of the 

 western States. A cache at Beardstown, Cass County, Illinois, con- 

 tained 1,500 implements, arranged in horizontal layers, separated by 

 thin strata of clay. Another deposit, of 3,500 specimens, was found in 

 Fredericksville, Schuyler County, Illinois. The largest of such nodules 

 in the U. S. National Museum, from a deposit in Union County, 

 Illinois, is of ovoid form and measures 1^ inches in length by Oi inches 

 in width. 



The following excerpts from the report on the Pentamerous limestone 

 of the Clinton group, by Prof. James Hall,^ sliows that flint exists both 

 in strata and in nodules iu the indicated horizon and locality: 



On the Genesee River this rock outcrops on either side. In many places in Wayne 

 and Monroe counties it contains nodules of hornstone which sometimes assume the 

 form of chalcedony. This matter increases so ranch iu Orleans and Niagara counties 

 tliat it forms thin layers alternating with the limestone. Associated with this chert 

 are found silicitied fragments of shells and crinoidal joints. South of Modena thin, 



'Manual of Mineralogy and Ijithology, 1886, p. 237. 



2 Geology of the Fourth District of New York, Pt. IV, 1843. 



