30 



and Dictyonema. The Levis is thus to be correlated with 

 similar deposits low in the Ordovician of Europe. 



Very fossiliferous pebbles have been found in the con- 

 glomerates in the Levis, and the fossils show them to be 

 derived from strata of three geological ages. The pebbles 

 are: 1st, Lower Cambrian limestone with Olenellus, Salt- 

 er ella, etc.; 2nd, Upper Cambrian or Lower Ordovician, 

 ("Tremadoc" or "Ozarkian") with Symphysurus, Dike- 

 locephalus, etc.; 3rd, Beekmantown, with Lloydia saffordi, 

 Camarella calcifera, and a great variety of brachiopods 

 and cephalopods. Besides the limestone pebbles there are 

 many of igneous rocks and quartzites, but they do not form 

 nearly so large a proportion of the conglomerate as do those 

 composed of limestone. The conglomerates also contain 

 pebbles of the red and green shale and sandstone of the 

 Sillery, thus proving that the Sillery is older than the 

 Levis, while the presence of Beekmantown fossils in both 

 pebbles and matrix of the conglomerates shows that the 

 Levis is of the same age as the Beekmantown at Philipsburg, 

 Quebec. There are no outcrops of limestone containing 

 the Olenellus fauna nearer than Labrador, 500 miles 

 (800 km.) northeast of Levis; the nearest outcrop of lime- 

 stone containing the Dikelocephalus fauna is at Whitehall, 

 N.Y., 250 miles (400 km.) southwest; and the nearest 

 outcrop of fossiliferous Beekmantown is at Bedford, Que., 

 150 miles (240 km.) southwest of Levis. Yet the vast 

 numbers and often large size of the pebbles in the con- 

 glomerates indicate that the older limestones outcropped 

 near the basin where the Levis shales were formed, and 

 it seems very probable that such beds now exist somewhere 

 to the southeast of Levis, entirely buried by the shales 

 which have been thrust over them. 



SILLERY FORMATION. 



The Sillery is the oldest sedimentary formation now seen 

 in the district, and very little is known of it. It consists of 

 red and green shales, and lenticular masses of red and 

 green sandstone. Like the Levis it is thrown into tightly 

 compressed over-turned folds, and contains so few hard 

 beds that it is practically impossible to work out its detailed 

 structure. With the exception of the little inarticulate 

 brachiopods, Linarssonia pretiosa, fossils are almost 

 entirely lacking. The few that have been found, species 



