what are solution caves in sandstone?

Question

how do they form and what are some exmaples of hwere this type of cave can be found..

Answer 1

"Sandstone caves form through differential weathering along a shale-sandstone contact. Massive, cliff-forming sandstone can contain soft, erodible beds of shale. Water readily percolates down through sandstone but is trapped and cannot pass through shale beds because their pore spaces are so small. The groundwater is forced to move laterally along the contact between the two rock units until it seeps out on the face of the canyon wall or at the back of an alcove, creating a spring or seep. The prolonged flow of water along these spring and seep zones ultimately dissolves the calcium carbonate cement and loosens individual sand particles and blocks of sandstone, thus forming a void that enlarges with time." From National Park Service website (therefore not copyrighted) at url below.
http://www2.nature.nps.gov/views/KCs/CaveKarst/HTML/ET_Intro.htm

Most folks would not classify a sandstone cave formed in this manner as a solution cave...but, since the process involves the dissolution of the cement of the sandstone, in a way, it is.

Valley of Fire, Nevada.
http://www.livingwilderness.com/southwest/vof-beam.html
Fountain Cave, Minnesota
http://www.nps.gov/archive/miss/maps/model/fountain.html