Lrockport. The contact is absolutely emphorable but the lithology med side | the contact is very different. The Rochester blue shales are followed by then redded gray dolomites and all along the contact line we can see weathering out the iron pyrite sandy basal layer we saw yesterday at Hamilton. Could not get at it to prove this. There appear take about 20 feet of Lrock port and than come in the clark heavily much then more redded dolomites. The latter prevences here about 12 feet. TJ J Ormountain.