﻿78 Scientific Intelligence. 



cal atlas of the United States ordered by the General Govern- 

 ment, has had topographical surveyors in the field, in different 

 parts of the country ; and the forty-five maps now issued are part 

 of the results thus far completed. They cover portions of Utah, 

 Nevada, Arizona, Texas, Missouri, Kansas and Alabama. Each 

 comprises about one degree in latitude and the same in longitude, 

 and measures IV to 18 inches by 12 to 14. Altitudes are marked 

 by contour lines, with the addition of numerals on the peaks or 

 higher points, and the rivers are printed in blue. The maps are 

 finely engraved, of convenient size, and beautiful in appearance ; 

 and when completed and supplied with geological coloring and 

 details, will be esteemed at home and abroad as very important 

 work well done. The country is large and the expense will be 

 large ; but the great work should be carried through to its full 

 completion whatever the cost. 



4. Stromatopora. — Dr. C. Rominger criticises the paper of 

 Nicholson and Murie on the structure of Stromatopora, in the 

 Proc. Nat. Sci., Philadelphia, of 1886, pp. 39-56. 



5. Paloeontologica Indica. — Numerous Bryozoa, Annelida and 

 Echinodermata of the Productus Limestone in the Salt Range, 

 are described by Dr. Wm. Waagen in a part of the quarto pub- 

 lications of 1885, and beautifully illustrated on plates 87 to 96. 

 All the plates but two are devoted to the Bryozoa. The 

 author excludes from the Bryozoa the genera Chsetetes, Steno- 

 pora, Monticulipora, regarding them as probably belonging with 

 the tabulate corals, and includes therefore only two families, the 

 Fenestrellidse and Thamniscidse. 



6. Microscopic characters of some specimens of devitrified 

 glass ; by D. Henma^ and Frank Rutley, (Proc. Roy. Soc. 1885, 

 p. 87). — The authors describe the effects obtained by microscopic 

 examination of various specimens of devitrified glass. Devitrifi- 

 cation was obtained by covering the floor of the kiln with 2-j- inches 

 of sand, putting on this the glass, and then a layer of sand 3 and 

 6 inches thick. By slow heating, in six days the glass had become 

 dull red, and in six more a bright red, without fusion. This 

 temperature was maintained for twelve days and then the kiln 

 opened and quickly cooled. In other experiments, the time was 

 varied. It was found that with heating for twenty to thirty 

 days, as above described, the glass was thoroughly devitrified ; 

 that if the heat was kept below dull red heat, or about 650° F., 

 there was no devitrification ; and if cooled immediately after heat- 

 ing to 650° F., allowing four hours for the cooling, the devitrifi- 

 cation was slight and mostly on the surfaces. The devitrification 

 goes on from the surface inward. When least complete, stellate 

 or radiating crystallites are formed ; and when a little more so 

 there is usually a tendency to a spherulitic structure; and when 

 complete, it is generally a mass of more or less distinct divergent 

 groups, separated sometimes by "an angular outline. There are in 

 some cases spherulites, with or without a radiated structure. 



7. JE. 0. UlriclCs Contributions to American Palaeontology, 

 Vol. I. Cincinnati, 1886. — Mr. Ulrich in his prefatory remarks 



