BIBLIOGRAPHIC REFERENCES. 57 
that accompany geological and mining reports and papers, that certain 
of them or portions of them would serve very well for plans of clay-veins, 
such as figures 6 and 7 (page 40) of this paper, but want of time forbids 
a reperusal of the mining literature in which such plans appear in order 
to give the references. ‘The thought which occurred to me in this con- 
nection is that it may be possible that the same causes which pro- 
duced the fissuring of the Coal Measures may also have been the origin 
of some of the well known fissure veins of metalliferous mining regions. 
The author conceives that during geological time there may have been 
many periods at which a rending of the strata, such as that which hap- 
pened to the Coal Measures and gave birth to the clay-veins, may have 
occurred in one region or another, and to such fissuring probably some 
of the phenomena to which book references are given at the close of this 
paper is attributable. 
The foregoing suggestion, subject, of course, to verification, is offered 
in the hope that it may prove of value in future investigations. 
BIBLIOGRAPHIC REFERENCES 
For those desirous of looking further into this subject, the following 
references may be useful : 
Transactions London Geological Society, vol. 5, 1821. On pages 382 and 407 are descrip- 
tions of clay-veins or dikes of diluval gravel in the rocks near Great Pulcovea, 
near Saint Petersburg, Russia. 
Quarterly Journal Geological Society of London, vol. xxx. On page 731 there is refer- 
ence to schistose dikes in shale in Newfoundland. 
Concerning alluvial veins in the Carboniferous limestone in England : Quarterly 
Journal Geological Society of London, vol. xxxvii, p. 67. 
Ossiferous fissures in Kent, England: Quarterly Journal Geological Society of London, 
vol. L, p. 170. 
H. W. Bristow: Mines and Miners, 1868, figure 1, plate xvi. 
Daddow & Bannon: ‘‘ Coal, Iron, and Oil,” 1866, pages 295 and 678. 
Louis Figuier: ‘‘ Earth and Sea,” 1870, figures 130 and 131, page 372. 
Transactions North of England Institute of Mining Engineers, vol. xix. On page 146 
there is a description of masses of shale in coal in Nova Scotia. 
On breccia gashes of the Durham coast, England: Transactions North of England 
Institute of Mining Engineers, vol. xxxiii, 1883, page 165. 
Economic geology: Ohio Geological Survey, vol. v, page 143. 
Annual Report Pennsylvania Geological Survey, 1886, part 1, page 447. 
Pennsylvania Geological Survey, vols. K, KK, KKK, and Q. 
Pennsylvania Geological Survey, vol. K 4, 1884, pages 48, 50, 60, 62, 121, 163, 178, and 
187. 
