564 abstracts: geology 



The report discusses the causes of the burning and its general effects 

 on the overlying strata, and includes petrologic descriptions and photo- 

 micrographs of some of the slags formed. An attempt has also been 

 made by means of chemical analyses to explain the mineralogic com- 

 position of the slag. As the original rocks are argillaceous rather 

 than calcareous the minerals formed are unlike those common in ordin- 

 ary furnace slags, and resemble those investigated by Morozewicz in 

 his study of the aluminous magma. G. S. R. 



GEOLOGY. — A comparison of Paleozoic sections in southern New Mexico. 



N. H. Darton. U. S. Geological Survey Professional Paper 108-C. 



Pp. 25. 1917. 

 In studying the geology of southern New Mexico, it has been found 

 that various formations of Paleozoic age outcrop extensively in sev- 

 eral ranges not previously examined, and many peculiar features of 

 stratigraphy and overlap are presented. Representatives of parts of 

 Cambrian, Ordovician, Silurian, Devonian, and Mississippian time 

 occur. These rocks thin to the north and disappear near latitude 34°, 

 beyond which the Pennsylvanian formations lie on pre-Cambrian gran- 

 ite and schist. The overlap relations of the rocks of the various sys- 

 tems are somewhat complex, and it has not been possible to ascertain 

 to what extent the absence of certain formations is due to non-deposi- 

 tion or to removal by erosion. It was found that the Bliss sandstone, 

 El Paso, Montoya, and Fusselman limestones, Percha shale, and Mis- 

 sissippian limestone are well represented in the San Andres Mountains, 

 most of them extending to its north end. They are also exposed in 

 the great section on the west slope of the Sacramento Mountains south- 

 east of Alamogordo. The El Paso, Montoya, and Fusselman limestones 

 are prominent in the Lake Valley, Caballos, and Cooks Range uplifts, 

 as well as in some of the ranges in Luna County. The formations are 

 remarkably constant in their characteristics and yield many distinctive 

 fossils. N. H. D. 



GEOLOGY. — Oil resources of black shales of the eastern United States. 



George H. Ashley. U. S. Geological Survey Bulletin 641-L. 



Pp. 12. 1917. 



It has long been recognized in tlyis country that the time would 



come when the decline of yield in the oil fields would lead to tests of 



the black shales as a possible source of oil. 



The black shales of the eastern states are mainly at one general 



