236 AMADEUS W. GRABAU 
tion here contains remnants of the Lorraine fauna with Byssomichia 
radiata and other types. These beds are clearly the lower Juniata, 
for the base of the series is seen in contact with the Bald Eagle con- 
glomerate not far away. The maximum thickness of the Juniata in 
central Pennsylvania is from 1,000 to 1,200 feet. On the Niagara, 
the corresponding Queenston shale is 1,100 feet thick, and it thins 
away almost wholly before reaching Michigan, where only a few 
red beds mark the summit of the Ordovicic. 
The Juniata has all the characters of deposits in arid regions. 
The total absence of fossils, except where, at the beginning, a lagoon 
extended north into Pennsylvania, is a striking feature. That 
fossils could be preserved in the formation is proved by the occurrence 
Appalachian Region 
Interior Region 
= ———— 
t SSS Av|\ 
eZZz_ZZ SES 
= 
—s I 
Zhou 
Seal T T == = = 
Maysville—T = i =Lorraine =o 
mE herein | aa 
(ee SS r i‘ I I r T 
ee eS a a Trenton! L i r I 
T 
r = 
T if Cr tt tt tt 
I 
I 
T 
Marine Series _ Continental Series 
Fig. 10.—Diagram showing relationships of marine and continental upper Ordo- 
vicic and lower Siluric strata. The conglomerate beneath the Juniata is the Bald 
Eagle, and beneath it is the Eden sandstone. 
of Lorraine species in the basal beds. Their absence from the others 
must then be taken as indicating that none were inclosed in the 
strata. This absence of fossils, together with the character of the 
beds, their red color, frequent mudcracks, and numerous clay slugs 
or ‘“Thongallen’” in the sands, and the aeolian cross-bedding, 
all point to a continental origin, under conditions of semiaridity and 
tropical climate. That the Juniata and Queenston beds are equiva- 
lent, and were formed under the same physical conditions, cannot 
be doubted. Their correspondence in thickness indicates an almost 
complete equivalency. They may, however, have distinct sources, 
one in the southeast and the other in the north. In western New 
York the Queenston shales are succeeded by the true Medina sand- 
stones and green shales, which are partly fossiliferous, carrying a true 
