abstracts: geology 515 



The older formations of the region comprise more than 20,000 

 feet of strata ranging in age from Algonkian to Pennsylvanian. These 

 rocks were intruded by large masses of granite in late Cretaceous or 

 early Eocene time. Great volumes of andesite lava flooded a system 

 of deep valleys in Miocene time, and extensive outpourings of basalt 

 during the Pliocene have covered parts of the region. 



The principal ore bodies are contact-metamorphic copper deposits. 

 They are of particular scientific interest because they appear to have 

 been formed by gaseous transfer from a granite magma, during which 

 large quantities of iron, aluminum, silicon, copper, and sulphur were 

 supplied to the contact rocks. The geologic relations are unusually 

 favorable and allow almost rigorous proof that the ore-depositing 

 solutions were of magmatic origin. The copper deposits are highly 

 oxidized, and chrysocolla is the main constituent. Many of the fea- 

 tures of the oxidized ores appear to be of colloidal origin, and the prev- 

 alent microscopic banding is probably due to rhythmic precipitation 

 in gelatinous media (the Liesegang effect). A. K. 



GEOLOGY. — The Newington moraine, Maine, New Hampshire, and 

 Massachusetts. Frank J. Katz and Arthur Keith. U. S. Geol. 

 Survey Prof. Paper 108-B. Pp. 11-29. 1917. 



A recessional moraine consisting of several separate segments dis- 

 posed along a sinuous course lies near the Atlantic coast and has 

 been traced through 60 miles from Saco, Maine, to Newbury, Massa- 

 chusetts. It is for the most part about or less than 100 feet above 

 sea level but rises to 180 feet in Biddeford, Maine, 150 feet in Dover, 

 New Hampshire, and Newburyport, Massachusetts, and is between 

 200 and 250 feet above the sea in Wells and South Berwick, Maine. 

 Although not more than 40 to 100 feet higher than surrounding Pleisto- 

 cene' formations, nevertheless it is topographically prominent because 

 it is in a region of slight relief. The moraine rests upon and is sur- 

 rounded by a floor of ice-smoothed rock and of till. The region was 

 submerged during the building of the moraine, and the ice front stood 

 in the sea. The moraine is the result of the accumulation of glacio- 

 fluvial detritus discharged directly into the sea; consequently in some 

 places it is built up as broad, flat, delta-like plains of sand and gravel. 

 Clay ("Leda clay") was continuously deposited in the sea, both while 

 the moraine was accumulating and after the ice retreated from the 

 moraine, so that the younger clay beds in some places overlie the 



