286 E. H. WILLIAMS, JR. EXTRAMORAINIC DRIFT. 



and below by damourite slates, and that its lower portions are niagne- 

 sian, as well as argillaceous and sandy ; so that in the eastern part of the 

 region (Bethlehem) it weathers to a clayey sand, and, in the western, to a 

 reddish, porous sandstone that sometimes, when coarse, resembles the 

 rotten bands of the flags in the Hudson river formation. This latter 

 formation is well defined by the term " slate belt," as the above bands 

 are thin and infrequent. The formations north of the Clinton occasion- 

 ally carry fossils, and their determination is based thereon. 



GLACIAL DEPOSITS. 



The Fringe. — The extramorainic deposits of the region are called a 

 " fringe " to the moraine because they seem to be closely allied to it 

 in time of formation, and not because they are attenuated. They are, 

 on the contrary, of great bulk, and worthy of comparison with the mo- 

 raine in its greatest extension. This will not be used as an argument for 

 an extension of time necessary for their formation ; but, on the contrary, 

 the survey of the region shows such a recency of creation that we are 

 compelled to admit great rapidity of accumulation, as advocated by Mr 

 Upham, and, applying the same rule to the moraine, are enabled to com- 

 press all the glacial deposits into a short period that can be measured 

 by tens instead of hundreds of thousands of years. It may be argued 

 that such a bulk of material would not have escaped the attention of 

 the state survey. The above extracts show what was done with the evi- 

 dence adduced twenty years ago by Professor Prime, and it must be 

 stated that local and limited surveys of the region are extremely con- 

 fusing, and might lead to the decision that the deposits are due to water 

 alone. It is only when the region is studied as a whole that the clue to 

 the mode of action can be obtained. Any thorough search, however, 

 would have shown subglacial till within the limits of the region mapped ; 

 but this was so capped by lake deposits as to be unseen except under 

 special circumstances. There was no reason, however, for calling the 

 unstratified till to be found in railroad cuts atBingen, South Bethlehem, 

 Northampton, Siegfried, and other places stratified material* though 

 it is not common to find subglacial and englacial till composed almost 

 wholly of river pebbles, and on this account an extended discussion of 

 the till and the capping is necessary. 



T/ie Packer Clay. — A lake formed by the damming of the Lehigh by 

 the glacier was noted on the map within the contour line of 500 feet. It 

 is proposed to call this lake Packer, in honor of the late Honorable Asa 

 Packer of Mauch Chunk. Judge Packer, as the builder of the Lehigh 

 Valley railroad and the founder and munificent endower of the Lehigh 

 University, was preeminent in the development of the region mapped 



