Artist Signature Unknown...Please help

Hi members -

I picked up these very neat pieces. I originally thought they were etchings however upon closer inspection they appear to be done in graphite or pastel. The pieces are on paper and as you can see there is noticeable foxing as the pieces were not framed with preservation in mind. Aside from getting any info on the artist to possibly get an idea on the age, I am having both reframed for preservation. Any help with identifying the artist would be greatly appreciated. Many thanks!

http://imgur.com/a/d9Tmn