Silurian Strata near Penobscot Bay, Me. 415 



Feet. 

 Brown- or ochre-weathering, dark bluish-gray, impure lime- 

 stone, J IV, LlV, probably O. Fossils distinguishable only 



on weathered surfaces 21 



Concealed V5 



Light colored porphyry, J 14, L 14 .. 3 



Dark bluish-gray indurated shale (J and L 13-8), slightly 

 calcareous in places, sometimes with calcareous nodules, 

 greenish-gray in upper portion. Many fossils at L 12 and 

 some at L 9. The plane in which fossils lie at L 12 shows 

 the strike at that point to be N. 55° W., dip K 35° E., V0°. 

 Exposure not continuous either on J or L. In detail, on 

 J, — shale, dipping at top S. 8° W., 55°, 1 15 feet ; concealed 

 22'; shale 20'; concealed 15'; shale 8'; concealed 20'; 



greenish-gray shale (J 8) 45' 203 



Red shale (holding nodules of white limestone at one point), 

 red and white sandstone and conglomerate, J V, dip S. 9° 



W., 60° ; L V, low tide exposure only 42 



Various, usually hard, argillaceous, occasionally calcareous, 

 beds, with subordinate strata of limestone, frequently 

 cross-bedded, with varying strike and dip (J 1, S. 35° E., 

 65°; J 2, vertical; J 5, S. 10° W., 56°; K 1, S. 14° E., 

 65°; L 1, K 25° W., 80°; L 2, vertical; L 3, N. 20° W., 

 68°-85°; L 5, S. V0°) ; f ossiferous at J 6, 5, 2 (the first 

 two respectively 42 and 85 feet above the red beds) ; K 1 

 (about 125 ft. above the red beds), K 2 ; L 5, 4, 2, I ; 

 thickness about .. 1V5 



Total 606 



This is obviously a shore and shallow water deposit. 



The band of porphyry low in the section, J 14, L 14, seems 

 to follow the bedding, but at L 14 is seen to extend northward 

 and cross the underlying strata. 



The eruptive rock south of the f ossiliferous beds cuts across 

 them (N 1), and at one place (M) was seen surrounding a 

 fossiliferous fragment of one of the highest beds in the series. 

 jSTear the contact, the stratified rocks are disturbed and some- 

 times violently twisted and broken (N 2). 



Within the mass of the eruptive rock are included some 

 strata which appear to be higher in position than the fossil- 

 iferous rocks above described. A long band of coarse con- 

 glomerate extends from near the peak of Ames's Knob to the 

 shore of Southern Harbor just north of a stone wall which is 

 indicated on the Coast Survey charts. A sandstone layer in 

 this conglomerate gave the strike IN". 55° E. Still farther 

 south, half way from the wall to the shore of the Thorough- 

 fare, and 120 yards east from the bay east of Turnip Island, 

 red shales and fine sandstones (strike IN". 68° W., dip S. 22° 

 W., 60°) are surrounded by the eruptive rock, which is seen 

 crossing the beds. 



