Topographical Features of the JVew Haven region. 47 



Tom, 1211 feet. (The last four altitudes are from Prof. Guyot's 

 measurements.) Although the precise original elevation of the sand- 

 stone about these heights is not certain, there is no doubt of the great 

 increase of height to the north.* This however was not one of the 

 original conditions of the rock, for the beds were made in one com- 

 mon estuary aid nearly to a common level. It has resulted from an 

 uplift which affected the interior of New England more than its south- 

 ern borders ; and the trap also owes much of its greater height to 

 the north to the same uplift. 



The sandstone mass intersected by dikes of trap constituted the 

 block out of which the future ISTew Haven region was to be carved by 

 various denuding forces. The hard dikes of trap, and the distribution 

 of the hardened sandstone among those feebly hardened, had great 

 influence in guiding the modeling agencies and determining the 

 future features of the country. 



At the time of the eruptions, or soon after, the land before sul)mer- 

 ged rose above the level of the waters ; rivers took size and direction 

 according to the slopes ; the estuary dwindled into the Connecticut ; 

 and the Connecticut, finding in its way the trap dikes of Weathers- 

 field, Berlm and Meriden, and also elevations of sandstone, took a 

 route, in the latitude of these hills, to the eastward. So the river 

 was lost to New Haven.* Other changes in the old hydrographic ba- 

 sin of the Connecticut valley have taken place since the throwing up of 

 the trap dikes, and part of the following may date from that event, 

 Farmington river, which in Triassic times flowed into the estuary from 

 the western heights of Massachusetts and northern Connecticut, still 

 enters the Farmington region ; but near Farmington it turns abruptly 

 north, flows in that direction sixteen miles, at the foot of Talcott moun- 

 tain and other trap hills of the range, then makes a cut through the 

 range into the Connecticut river valley and joins that river. The 

 Quinnipiac, which starts in the Farmington valley just below the 

 northward bend of the Farmington river, on approaching the region 

 of the trap hills of Cheshire bends eastward out of the valley in front 

 of the Hanging Hills of Meriden, into the valley where the Connec- 

 ticut river might have had its course but for the trap eruptions and 

 disturbances ; and finally, the Farmington valley being thus deserted 

 by the Quinnipiac, Mill river at this point commences its flow, taking 

 its rise in the adjoining hills, • and becomes the principal stream for 

 the rest of the valley southward to New Haven bay. 



During the Cretaceous period closing the Reptilian age, and the 



* This view was brought out by the writer la Ward's Life of Percival, p. 420. 



