Hot springs the world over register their presence by leaving deposits of unusual minerals, and they have left this sort of record at Loudville. Here the coarse sandstones of the lowland rest upon gneiss, and at the south end of the Loudville lead vein barium sulphate crystals, called barite, formed in the sand before it was cemented into solid rock. The crystals are the product of highly charged mineral water, rising through the sands from a subjacent fissure. The fissure itself is also filled with barite, and with galena and quartz as well. It is the vein which was worked in the old Loudville lead mine. There are other veins in the western and eastern highlands at Hatfield, at the Northampton reservoir near Whately, and at Leverett. All are in fractures which were still partly open when the valley first took form. _The Marginal Uplands_ The rocks which formed the high eastern mountain range of Triassic time and the rocks which made the old western hills and underlay the basin floor comprise essentially a single group characterized by its complexity. At one place the rock resembles sandstone, but the layers stand on end; at another, it looks like shale, but the stone breaks across the color banding instead of parallel to it; and at a third place a fissure seems to have opened and had a crystallizing melt poured into it. These tabular, filled fissures can be found nearly everywhere, coursing in every direction and at all conceivable inclinations to form a network that binds the older rocks into a firmly knit whole. The fillings, or dikes, are like reinforcing rods, holding the rocks together and withstanding the agents of destruction. Thus, the story of the highlands has three distinctive phases,—a relatively young phase when the interlacing reinforcements were poured into fractures; a somewhat more remote stage, when the bedded rocks were crumpled into their inclined positions; and an earlier stage, when the bedded rocks were deposited. The geologic dates of these three events may vary from one locality to another, and they certainly are different in the Eastern Upland as compared with the Western Upland; but the events always occurred in this sequence and constitute the broader aspects of the story at all places. [Illustration: Fig. 12. _Block diagram showing topography during formation of the lead veins._] _The Eastern Upland_ The Eastern Upland includes the land between the Connecticut Valley and the Atlantic Ocean. At present, it has the general form of a broad rolling highland with ridges and valleys that have a north-south trend. Close inspection shows that the rocks in the ridges are different from those in the long valleys. Also the layering of the materials ranges from a vertical attitude, as at Ware and Brimfield, to undulating and almost horizontal positions, as at Spencer and Worcester.