MAE YL AND GEOLOGICAL SURVEY 155 



Section one and one-eighth miles east of Principio Creek. 



Formations. Feet. 



Recent. Loam-bearing gravel 5 



Raritan. Fine white sand 11 



Brown loamy sand, bearing gravel and arkose toward base 12 



Patapsco. White clay, somewhat iron-stained and variegated ; at times grad- 

 ing over into micaceous sands; changing to gravel, arkose, 



conglomerate toward base 10-20 



Dense, variegated clays. 10 



The fossils of the Patapsco formation in this county consist of 

 ferns, cycads, conifers and a few dicotyledons. Species of the latter 

 found in the uppermost beds possess well-marked modern affinities. 



THE RARITAN FORMATION. 



The Raritan formation is so called because of its typical develop- 

 ment about Raritan Bay in JSTew Jersey. Its age, judging from the 

 plant remains which are found imbedded in its clays, is Lower Cre- 

 taceous. It lies unconformably on the Patapsco, and is overlain 

 unconformably by the beds of Upper Cretaceous age. The Raritan 

 formation occupies the greater part of the high land of Elk Neck, 

 extending from the Baltimore and Ohio Railroad on the north to 

 Turkey Point on the south. It is underlain throughout this district 

 by the Patapsco formation which is found exposed in the lowland 

 bordering either side of the peninsula, as well as in the beds of the 

 streams which cut through the Raritan formation. On the east side 

 of Elk River, the Raritan formation is also found occupying the low 

 ground along the river and occupying the beds of the streams for a 

 distance of _3 or 4 miles. East of the Elk River it rapidly disappears 

 below the overlying beds of younger age. Besides these continuous 

 areas of Raritan, there are also a few outliers of the same formations 

 which are found at Singerly near Childs, at Egg Hill, at Foys Hill 

 and at the hill to the northwest of it. 



The materials of the Raritan formation are similar in kind and in 

 distribution to those making up the Patuxent and Patapsco form ra- 

 tions. They consist of variegated clays and horizontally stratified 

 and cross-bedded sands, gravels, sandstone and conglomerate. They 

 are not regularly developed over great 'areas, but change abruptly 



