Sounds like holey limestone. I use a local ditributor who ships nationwide, I've been told.

Semco is their name, and they're located in Perryville, MO, just South of St. Louis.

I have 3 truckloads = about 20 ton . I have a friend who will sell it by the semi-load. I am in northern Missouri,
He is in central Kansas and is excavating holey rock - year round. can ship anywhere in the USA. affordable prices.
ichiefdave@yahoo.com for more info.

You can call Southern Stone. They have cheap Texas Holey Rock and don't have a minimum qty. Of course, the more you buy the cheaper it is. 956-464-9979