482 REPORT OF NATIONAL MUSEUM, 1904. 



of the Geological Society of America, and president of the Interna- 

 tional Congress of Geologists in 1891, although then too ill to attend 

 its meetings. 



April 20, 1857, D. D. Owen, while State geologist of Kentucky, was 

 appointed by the governor of Arkansas geologist of that State, the 

 appointment to take effect "from and after the first (Jay of October, 

 David Dale and 1857," at which time it was supposed the Kentucky 



Richard Owen's work would be brought to a close. Owen selected for 



work in Arkansas, » 



1857-1860. h} s assistants, E. T. Cox and Leo Lesquereux, with 



Joseph Lesley, for topographer, and Robert Peter and W. Elderhorst, 

 chemists. Two large octavo volumes, comprising together some 689 

 pages, were issued in 1858 and L860, the first having been printed 

 apparently at Little Rock and the second in Philadelphia. They were 

 illustrated with colored lithographs and engravings after originals in 

 Owen's well-known style. 



On paleontological evidence the zinc and lead-bearing rock of north- 

 western Arkansas, i. e., the 300 feet of Magnesian limestone and silico- 

 calcareous rock that underlie the marble strata, forming about 250 to 

 300 feet of the lower and main body of the ridges of Marion County, 

 were put down as of Lower Silurian age. and as in all probability 

 belonging to that subdivision known as the Caleiferous sandrock of 

 the New York system. The "marble limestones' 1 of northwestern 

 Arkansas he was unable to fix definitely, but seemed to think it prob- 

 able they would prove to represent the Onondaga of New York. 



As to the origin of the lead ores, he wrote: 



My impression is that the lead ore once occupied these north and south crevices, 

 and was subsequently removed, in part or in whole, into its present bed by trans- 

 portation, analogous to that known to mineralogists under the name of the pseudo- 

 morphous process, by which one mineral is removed while another takes its place, 

 assuming often the form of the first mineral instead of the usual form belonging to 

 itself. * * * That it should have been deposited like a limestone or sandstone 

 is altogether improbable, and contrary to the usual nature of such ponderous and 

 difficultly soluble minerals. 



The cause of the hot springs Owen considered to be the "internal 

 heat of the earth.'' Not that the waters came actually in "contact 

 with fire,'*' but rather that they w T ere completely permeated with 

 "higbJry heated vapors and gases which emanate from sources deeper 

 seated than the water itself." 



The snowy white novaculite from the vicinity of the hot springs he 

 believed to be of the age of the millstone grit, and "once a simple 

 ordinary sandstone. From the state of ordinary sandrock it has 

 been altered or metamorphosed into this exquisitely tine material, not 

 as I conceive, by contact with fire or igneous rock, but by the per- 

 meation of heated alkaline siliceous waters." Through this permea- 

 tion he conceived that "the particles of solid rock have been gradually 



