230 Proceedings of the Boyal Physical Society. 



theory" of Voh Eichthofen may, however, be applicable 

 also in cases where the Loss occurs at levels which rivers 

 could hardly reach. 



It is fine yellowish sandy or calcareous loam full of little 

 twigs and rotten sticks. It is often totally unstratifled, and 

 bears very little resemblance to an aqueous deposit. Here 

 and there stray pebbles and small patches of sand or gravel 

 occur, and on a more careful search minute shells are to be 

 found in abundance. These are terrestrial or lacustrine in 

 character, and bespeak a moist soil and mild climate. Some 

 of the chief species are Sitccinea oUonga, Helix hispida, H. 

 sericea, H. pulchella, Pupa muscorum, Achatina accicula. 

 Small marly concretions are found in the Loss which have 

 often grotesque forms, and are named Losskindel, Lossmann- 

 chen, etc. (loss babies, mannikins), by the German peasants, 

 who see in them a fanciful resemblance to new-born repre- 

 sentatives of genus homo. 



The newest deposit is the alluvium, which is carried down 

 from the Harz and spread in vast quantities along the banks 

 of the rivers as they debouch on the plains, where, losing 

 speed, they are obliged to relinquish the spoils they have 

 plundered from the higher regions. 



5. Massive Kocks of the Harz. 



In noticing these rocks it will be most convenient to follow 

 the order adopted by Lossen, and divide them according to 

 their geological ages into the following groups : 



! Diabase, interbedded and intrusive ; 

 orthoclase porphyry ; kersantite of 

 Michaelstein. 



! Granite and granitite, ampliibole granite, 

 quartz and augite diorite, gabbro and 

 enstatiterockSjkersantiteofLautenthal. 



! Quartz porphyry, orthoclase porphyry, 

 porphyrite and basalt (melaphyre) of 

 , Ilfeld. 



a. Pregranitic Eruptive Rocks. 



Diabase. — This is the most widely distributed volcanic 

 rock of the Harz, and occurs as interbedded and intrusive 



