120 GEOLOGICAL RECONNOISSANCE 



laxative in its effects ; but it is doubtful whether its alterative effects will 

 be as decided, since the proportion of sulphur appears to be less. As 

 iodides are usually an accompaniment of chlorides, this water will proba- 

 bly be found useful in reducing glandular swellings. 



At the blacksmith's shop, near the sulphur spring, I saw several speci- 

 mens of coal, found in this county, and obtained information in regard to 

 the localities of others ; viz., the Morrow coal, 14 inches thick, considered 

 to be the best for blacksmiths' use ; the Dyer coal, 12 inches thick, found 

 on the second bench of the Boston mountain, which is a heavier coal than 

 the former, but contains impurities ; Barnet's bank, about 11 inches thick, 

 on the waters of Cove creek ; and Store's bank, three quarters of a mile 

 beyond, and about the same thickness as that at Barnet's. 



On Cane hill, close by James Mitchell's house, the Archimedes limestone 

 is well exposed, and is quite cavernous. One cave, near Win. Mitchell's 

 house, is about 180 feet long, and seems to have been the resort of bears 

 and other wild animals, in former times. It occupies precisely the same 

 position as the one which 1 visited near Orion RieftY. The succession of 

 the rocks on Cane hill is only a modification of the preceding section. 



1. Fine-grained sandstone, 15 to 20 feet. 



2. Limestone, a few feet. 



3. Coarse yellow sandstone, 40 feet. 



4. Greenish grindstone grit, 45 to 70 feet. 



5. Archimedes limestone, 60 feet. 



6. Marly shales in the bed of the branch. 



The blacksmiths of Boonsboro obtain a coal from section 16, township 

 14 north, range 32 west, about three quarters of a mile from town ; it is 6 

 or 8 inches thick : this is the most westerly outcrop of coal known in this 

 county. 



Some iron ore is reported in Vineyard township, which I have not yet 

 examined. 



A bold spring issues at Boonsboro, from under a bench of Archimedes 

 limestone, 45 feet in thickness. The new College has been built on a 

 commanding point on the shaly sandstones that occupy the hill, immedi- 

 ately above the platform of limestone. Beneath these are dark shales, 

 succeeded, in the descending order, by an even-bedded, brown freestone, 

 very suitable for building purposes. The road to the Barren fork of the 

 Illinois river passes for several miles on this building-stone, which, being 

 often disjoined and displaced from the giving way of the underlying shale, 

 renders the road exceedingly rough. This underlying shale is of no great 

 thickness, and overlies chert and cherty limestone, which forms a mural 



