East Haven- Bradford Region. 369 



and caleite in the same cell. With the exception of this band 

 of amygdaloid the rock of this dike is compact and almost lus- 

 trous. This dike is a member of the third range west of Pond 

 Rock. The southern member of the first western range is 

 remarkable for the number of amygdules and "pipestems" of 

 caleite which it contains throughout its mass. A mile and a 

 half north of the railroad there is a similar occurrence of 

 amygdaloid. In both instances the trap is dull black in color 

 without apparent crystalline structure. Three miles from the 

 railroad the northern end of one of the members of this range 

 appears as a dike intersecting the layers of sandstone (D, on 

 the map). 



The relation of the sandstone to the trap. — If the sandstone 

 were oftener exposed in close proximity to the eastern slopes 

 of the ridges of trap, there would have been less opportu- 

 nity for discussion as to the relative age of the igneous rocks 

 and the sandstone. The southern members of the third western 

 range in and near the hill crowned by the New Haven Water 

 Co.'s reservoir in the southern part of the borough of Fair 

 Haven East are clearly seen to cut obliquely across the layers 

 of sandstone. The walls of these dikes are very regular, much 

 more so than those of the dikes in Wallingford and some other 

 parts of Connecticut. The southern end of the member of 

 this range next north of Hemingway mountain is exposed 

 within 200 feet of the end of that ridge. The exposure is in 

 the face of a bluff on the northern side of the road from New 

 Haven to North Branford, and shows an irregular mass of trap 

 lying between strata of sandstone. The latter is hard, mostly 

 compact, and bright red. Heat from the trap, probably 

 through the aid of moisture, has penetrated the joints of the 

 overlying rock,, vesiculating the sandstone. Tongues of trap 

 also have pushed their way into crevices of the overlying sand- 

 stone. The dip of the sandstone is eastward and high, but 

 was not satisfactorily determined. 



The ridges of the second western range cut somewhat 

 obliquely across the strike of the sandstone, but turn to the 

 north a mile and a half north of the railroad just before they 

 would otherwise have joined the first western range. No con- 

 tact, or sandstone near a contact, is visible except at one place, 

 where one small mass of trap shows itself in the road a third 

 of a mile west of Lyman Granniss's house (C, on the map), as 

 a distinct dike. Sandstone covers the top of the dike and 

 shows that it has been pushed up by the trap. The sandstone 

 beneath the trap of the first western range is exposed at many 

 places on the western slopes of the ridges ; but the overlying 

 sandstone has been almost completely denuded from the 

 ridges, its first occurrence being three miles from the railroad, 



Am. Jour. Sci.— Third Series, Vol. XXXVIII, No. 227.— Nov., 1889. 

 24 



