Puddingstone Jasper
The history of this rock starts in the Huronian period of the Proterozoic era, approximately one billion years ago. During this period, extensive sediments were deposited in or adjacent to seas, lakes, and other bodies of water. Much of this material, derived by erosion from the older rocks, was in the form of fine sand particles and rounded pebbles of gray and white quartz. The bright red and brown jasper pebbles were deposited over small parts of an east-west band about 50 miles long lying north and northwest of what is now Bruce Mines, Ontario, Canada. Sand, free of the pebbles, formed sandstone under the weight of later sediments, the individual grains becoming cemented by silicone and iron- bearing waters. Mixed sand and pebbles became conglomerates or sandstone conglomerates by the same process. Under the heat and pressures of later volcanic activity, sandstones and conglomerates were transformed into quartzite and quartzide conglomerates. Weathering and erosion uncovered some of the rocks, and loose fragments in great masses were gathered and moved by the Labrador portion of the continental ice sheets. [geocaching.com]