"so called boulders" lie in a limestone. I cannot see why the formation is called a limestone. It is true that it effervesces under hydrochloric acid, but the amount of lime carbonate present is not 20%. This rather muddy - sandstone cemented by lime. Richardson says the pebbles are of diorite, gneiss, porphyrite, quartzite and sericite schist. Of these I saw three unbroken and those belong to the formation and are not at all boulders or proper pebbles. He says "in some parts the pebbles are small, well sorted round, while the total conglomerate is highly crumpled and folded". There is no evidence that the pebbles are water worn. They are either cementations or rolled pieces of larch into stratified lith. One of the "boulders" was like this: The diorite pebbles maybe = Gneiss sandstone. Diorite granite on porphyrite. Richardson's "limestone" is a formation of very thin-bedded shales, sandstones every impure limestone. Any metamorphism into into a foliated - twisted schist. The "pebbles," are generally rolled in the foliation.