GEOLOGY AND PALEONTOLOGY OF THE SCHOHARIE VALLEY 337 



the seashore, a simple type of drainage soon became established 

 on it. Those streams which had formerly brought the material 

 from which the coastal plain was built, now continued their way 

 across this plain, following the slope of the land, and entered the 

 sea somewhere in the region of the present Mississippi valley. To 

 simple streams of this type the name " consequent streams " is 

 applied, since they are consequent on the slope of the surface on 

 which they originate. Streams of this type cut downward, mak- 

 ing valleys for themselves, which in depth are proportional to the 

 distance from shore, the slope and hardness of the strata and the 

 velocity of the current. At first these streams have no tributaries, 

 but these are gradually formed out of the gullies which are cut 

 into the sides of the valley of the consequent stream. Such 

 streams, mot controlled by original structural features, form the 

 type denominated " insequent streams." Some of these will in- 

 variably outstrip the others, and they will generally be the ones 

 near the old land, since here the river is higher above the 

 sea than elsewhere below and can cut its channel deeper; 

 hence the tributary insequents would have a greater slope and 

 therefore cut deeper trenches. In time these insequents will out- 

 strip their brethren which are farther down the course, and so 

 develop into the " subsequent " type, which near the upper end of 

 the coastal plain opens up a valley or inner lowland by removing 

 the strata immediately adjacent to the old land. The valley thus 

 formed will have on one side the hard crystallines of the old land, 

 while on the other there will be most generally a cliff of the sedi- 

 mentaries. The topographic element thus formed has come to be 

 known as a cucsta 1 and may be defined as a portion of a coastal 

 plain which has been separated by the normal processes of stream 

 erosion from the old land against which it originally lapped. The 

 essential features of the normal cuesta are a gentle surface slope 

 to the sea, and a steep escarpment or "inface," the precipitous- 

 ness of which will be in proportion to the resistance of the sur 



1 A name of Spanish origin, and proposed by Trot*. W. M. Davis Cor the 

 topographic type described, rrononnce k west a. 



