ZMAKVJ.AXD GEOLOGICAL SURVEY 51 



18S6. 

 Bextoim'. ED^VARD Ti. Kotes on the samples of iron ore collected 

 in Maryland. 



Tenth Census, vol. xv, Mining Industries of the U. S. AVashington, 1886, 

 pp. 245-260. 



Several sections of the strata exposed in iron mines near Beltsville, Branch- 

 ville, and Mnirkirk are given, together with analyses of the ores. 



McGee. W J. Geological Formations Underlying Washington 

 and Vicinity. Eep't Health Officer of the District of Columbia for 

 the year ending Jnne 30, 1885, pp. 10-21, 23-25. 



Abst. Amer. Jour. Sci., 3d ser., vol. xxxi, 1886, pp. 473-4. 



Speaks of the Columbia formation about Washington appearing "to repre- 

 sent a subaqueous delta of the Potomac river, formed when the sea rose far 

 above its present level and fashioned the marine terraces exhibited in the 

 bluffs. Its absence above sea level east of the Eastern Branch may be 

 attributed to a dislocation trending parallel to the Appalachians and the 

 Atlantic coast." The Potomac formation is also briefly described. 



Peale, a. C. Lists and Analyses of the ^Mineral fSprings of the 

 United States. 



Bull. U. S. Geol. Survey, No. 32, 1886, pp. 51-53. 



The saline and chalybeate Spa Springs at Bladensburg are included in the 

 list of Maryland springs. 



Pumpelly, p. Geological and Geographical Distribution of the 

 Iron Ores of the United States. 



Tenth Census, vol. xv. Mining Industries of the U. S. Washington, 1886, 

 pp. 3-36. 



Brief reference is made (p. 16) to the Potomac iron ores between Balti- 

 more and Washington. 



1887. 



McGee, W J. Ovibos cavifrons from the Loess of loAva. 



Amer. Jour. Sci., 3d ser., vol. xxxiv, 1887, pp. 217-220. 



"During the earlier epoch of Quaternary cold, the middle Atlantic slope 

 was submerged to a depth of over three hundred feet, and its rivers built 

 deltas at their embouchures into the expanded Atlantic along the inland 

 margin of the Coastal Plain of today." The ice-borne boulders brought down 

 by the Susquehanna at that time are said to have been fifty times as large 

 as those carried at the present time and those brought by the Patapsco and 

 Potomac twenty times the size of those of today. 



