Dauphin County Research Articles

Remarks on the bear valley coal district, in Dauphin county, Pennsylvania

This chapter explores the characteristics, distribution, and behavior and conservation status of the ringed seal. They are among the smallest of pinnipeds, with adults reaching a maximum length of 1.3–1.5 m and weighing up to 100 kg prior to breeding. Males and females are similar in size. It is a member of the subfamily Phocinae of the family Phocidae. The ringed seal is northern circumpolar in distribution. Although often considered as an inshore species, they have been observed at the North Pole and large numbers of animals are found in stable offshore pack ice in polar regions. Seal ecology is characterized by marine feeding combined with a need to haul out on a solid substrate for reproduction or molting. Although hauled out under these conditions they are often concentrated in large numbers, which facilitates attempts to estimate abundance using aerial surveys. Higher densities of ringed seals are observed in areas that combine stable first-year ice with a certain amount of irregular features such as pressure ridging or frozen in pieces of ice that would encourage snowdrift formation. Mating occurs in the water, and males are thought to defend underwater territories around a few females, but this has not been observed directly. There is some evidence of philopatry among mature animals, but juveniles may undertake extensive movements. Unlike many other seal species, ringed seals tend to be solitary and are widely dispersed, which provides some protection from direct commercial exploitation. The presence of stable ice and sufficient snow for the snow lairs is important for pup growth and survival.

Observations on the Trap Rocks of the Connewago Hills near Middletown, Dauphin County, and of the Stony Ridge near Carlisle, Cumberland County, Pennsylvania

Observations on the Trap Rocks of the Connewago Hills near Middletown, Dauphin County, and of the Stony Ridge near Carlisle, Cumberland County, Pennsylvania