JLhe expeditions under Koldewey and Payer, Ryder 

 and Nathorst, which had previously visited the parts of East- 

 Greenland in question, returned with a number of observations 

 on the geology and geography, the main characteristics of which 

 were thus already known before our visit. In consequence, I 

 considered that the time I spent up there as a member of the 

 Danish expedition of 1900, should be devoted in the main to 

 observing phenomena that had not up to that time been the 

 object of special study. 



Among my chief aims 1 took upon myself to collect a 

 considerable pétrographie material from a number of interesting 

 rocks, the occurrence of which in this region has already been 

 known since Scoresby's time. He mentioned the occurrence 

 of a series of porphyritic rocks, but little was known about 

 their age and nature at the time of our expedition. Then there 

 are a series of syenites and of peculiar basic eruptives, that 

 were Grst met with by Nathorst. Although we only worked 

 in the outskirts of the districts where these occur, while the 

 time that could be devoted to their study was also extremely 

 short, yet 1 succeeded in collecting a not inconsiderable ma- 

 terial for a pétrographie examination, calculated to clear up, 

 in some degree at least, the nature, age and distribution of 

 these rocks. Then there is the study of the archæan rock, 

 which has not hitherto been the object of special investigation 

 in these parts of the world; and, finally, the basaltic rocks, 

 which occur in very large masses with rich pétrographie varia- 



