CHAPTER II. 
THE ROCK FORMATIONS. 
SUMMARY. 
From a geological point of view the greater part of Green- 
land is an old continent, composed of crystalline rocks mostly 
of Archean age. Newer sedimentary formations of marine origin 
are met With near the coast in the northern and middle parts 
of Greenland. But the southern third of the country, south 
of 69° N. latitude, is extremely poor in sedimentary rocks. 
With the exception of the loam, sand, and gravel deposits of 
the Quaternary epoch, which on the whole occur in relatively 
small quantities, there have been found in southern Greenland 
only two small areas of post-Archean sediments, both at about 
61° N. lat., viz. the Arsuk group and the Red Sandstone. Since 
the only organic remains which have hitherto been detected in 
these sediments are sponge-spicules (in the Red Sandstone), 
an exact statement of the geological age is not possible. On 
the other hand, from the stratigraphical relations and the petro- 
graphical characters of the different rocks, and from a compa- 
rison of the sediments with those of East Greenland and of 
the north-east of Canada, we may infer not only the order of 
succession of the different rocks but also their probable geolo- 
gical age. In this way we arrive at the following classification 
of the formations of South Greenland: 
