Granites of Cecil County, in North-eastern Maryland. 107 



which is an ordinary shallow miner's pan or batea of twelve 

 inches diameter, and with an apical angle of 120 degrees. It 

 is best made of a single piece of spun copper, so as to leave 

 the interior perfectly smooth. In this pan is placed the pow- 

 dered rock or soil mixed with water. The mixture is stirred 

 thoroughly, and the water with the earthy portion in suspen- 

 sion is poured off. The granular portion so left is stirred 

 again in the liquid, by a combination of a spherical and 

 elliptical movement of the pan, which the hand soon acquires. 

 Then, by a quick side movement, the water is thrown off, 

 carrying the lighter minerals and the floating mica. After 

 several repetitions of this process, accomplished in a few 

 minutes, a small residue remains, which is mounted either in 

 balsam or water and placed under the microscope. This 

 method was applied to the decomposed granites at different 

 places within the granite area, and a number of facts were 

 thus brought to light which none of the thin sections revealed. 



The decomposed granites from five separate localities were 

 examined by this method. Three of these were near Liberty 

 Grove, one at Port Deposit and one near Perryville. To the 

 south of Liberty Grove, near the staurolite zone, there is a 

 bluff of decomposed granite by the side of the road, where 

 the first material was obtained. Small hemimorphic crystals 

 of tourmaline were found in the residue. Allanite was abund- 

 ant in small crystals, and it was also observed as an inclusion 

 in quartz. This mineral is strongly pleochroic, being deep 

 brown in the long direction and yellowish brown at right 

 angles to this line. Zircon is less abundant than at other 

 localities, and contains inclusions thought to be magnetite. 

 Large wine-colored gar?iets are scattered through the residue. 

 Other minerals noted in this soil were sp/iene, in large lozenge- 

 shaped sections (see Figure 6), small rutile grains, with 

 reddish yellow color. All the minerals of this soil were more 

 or less stained with iron hydroxide. 



In the granite soils further north, and especially in a 

 weathered bluff by the road, one-half mile north of the last 

 locality, zircon becomes the predominant mineral in the 

 residue, though it is only sparingly represented in the thin 

 sections. The crystals present a variety of colors, being 

 yellow, red and colorless. They occur in long narrow 



