My package of rocks included boulders and gravel sized rock. I could not use the larger rocks on my N Scale diorama; however, what was usable was very good. One very good feature of Woodland Sceniics rocks is that they take pigment very well--especially Woodland Scenics Earth Colors for sale on Hobbylinc.com. I used them for river bed talus, but they are also good for mountain scree and other detritus. Every layout needs this product.