Image: Peachbottom-Excelsior-Peerless Quarry Fig 2 Plate XXXI WBClark 1898

Description: Plate XXXI, Figure 2 of 1898 publication called Maryland Geological Survey Volume Two. Caption: Peachbottom-Excelsior-Peerless Quarry, Cambria, Harford County The text of the book refers to this figure as follows: The most prominent feature in the texture of the Peach Bottom slates is the coarse fibrous arrangement of the particles which give to the stone an appearance somewhat suggestive of the fibre of petrified wood. This texture renders the slates much stronger in certain directions than they might otherwise be but precludes the method of breaking the slates by sharp blows applied normal to the cleavage and makes the stock unavailable for milling purposes. The peculiar "fibrous" texture of the slate is indistinctly shown in Plate XXXI Fig 1 (sic) which represents the combined opening of the Peerless, Peach Bottom, and Excelsior quarries. This also renders the use of the plugging machines and similar instruments of doubtful value. It has also been found more economical and feasible to saw the slates across their grain. The material prepared for market shows little or no variation in the nature of the stone employed but the character of the finished product seems to vary somewhat in different quarries. Not only is there a difference in the skill with which the work is done but the quarrymen seem to differ in the amount of care which they exercise in sorting the first and second qualities. While different beds and different portions of the quarry furnish stock that differs in the ease with which it is worked and in the character of the finished product, the quarrymen say that good material may be obtained from all portions of the opening and at all depths below the zone of superficial weathering. In company with quarrymen from all regions the men hold to the belief that the rock improves indefinitely with the depth.
Title: Peachbottom-Excelsior-Peerless Quarry Fig 2 Plate XXXI WBClark 1898
Credit: Transferred from en.wikipedia to Commons. (Original text: Original publication: Maryland Geological Survey Volume Two, by W. B. Clark, 1898. Johns Hopkins University Press. Immediate source: Google Books [1])
Author: William Bullock Clark, State Geologist (Life time: 1860-1917)
Usage Terms: Public domain
License: Public domain
Attribution Required?: No