DO NOT TOUCH OR IN ANY WAY BOTHER THE PETROGLYPHS!!
In the middle of suburbia, tucked away from unknowing commuters and customers, lies the most accessible petroglyphic boulder in the Lower Southeast. This particular boulder was discovered during the construction of a branch of the First National Bank of Atlanta 100 feet from where it stands today. The boulder was relocated in 1984 to its current location for preservation. Upon discovery, the boulder was inspected and determined to be authentic by the in-house Cobb County archaeologist. Amazingly, the probable age of the petroglyphs on it range from 4000 BC to 2000 BC. Petrogyphs are found world-wide, except in Antarctica, and date back as far as 12,000 years ago. However, some petroglyph sites in Australia are estimated to date back 27,000 years, and still others are estimated to be as old as 40,000 years old.
The word "Petroglyph" comes from the Greek prefix petro-, from petra meaning "stone", and glýphō meaning "carve", and was originally coined in French as pétroglyphe. Petroglyphs are images carved onto the surface of a rock. The techniques used to create these images included pecking, incising, abrading, sculpting, polishing, drilling, and scratching. These carvings were carved with tools fashioned from diabase (a very hard volcanic rock found from Atlanta and eastward). Due to the softness of Soapstone, Petroglyphs can be susceptible to weathering by environmental factors, such as, acid rain. Often, they are covered with a protective seal to preserve the Petroglyph and help prevent such damage to its surface.
Soapstone (also known as steatite or soaprock) is a talc-schist, which is a type of metamorphic rock. It is composed largely of the magnesium rich mineral talc (yes, the kind that makes up the talcum powder that we use). It is relatively soft because of its high talc content. Talc has a value of 1 on the Mohs scale of mineral hardness (/moʊ/), meaning, it can be scraped with a human fingernail (which has a Mohs of 2.5). In comparrison, Topaz, a mere 8 on the scale of 10, will scratch glass. The Mohs scale is a qualitative scale which characterizes a mineral's resistance to being scratched based on the ability of a harder material to scratch a softer one. It was created in 1812 by German geologist and mineralogist, Friedrich Mohs. Softer grades may feel similar to soap when touched (hence the name). However, no fixed hardness is given for soapstone because the amount of talc it contains varies widely (impacting its softness). It can range from as little as 30% for architectural grades such as those used on countertops, to as much as 80% for carving grades. Soapstone is easy to carve, thus, making it ideal for the carving of bowls (as seen here) and other useful items. It is also durable, heat-resistant and has a high heat storage capacity. It has therefore been used for cooking and heating equipment for thousands of years. This particular boulder is unique in the fact that it has three different prehistoric feature types carved into the Soapstone.
1) Sprayberry Rock shows extensive evidence of bowls being carved from it. There are at least seven soapstone bowl preforms and bowl scars (where a bowl was actually made and removed) on the rock. One bowl (on the backside), was in the later stages of completion when it was abandoned.
2) There are many Cupules (the deep cup-like "pits") on Sprayberry Rock. These "Cupules" are seldom arranged in a recognizable pattern. It is thought they were used in the processing of nuts and acorns. In come cases, Cupules are considered an art form.
3) The third type of prehistoric feature on Sprayberry Rock is the petroglyphs themselves. This is considered an art from. There are at least three images of concentric circles carved on the boulder. While there are various interpretations on the meaning of concentric circles, it is impossible to determine at which point these circles were produced. If they are associated with the bowl carving, they are quite old. Concentric circles appear on other isolated petroglyph rocks throughout Georgia.
DO NOT TOUCH OR IN ANY WAY BOTHER THE PETROGLYPHS!!
To log this Earthcache, please complete the items below, and send them to the CO, preferably using the message feature in Geocaching.com:
Do *NOT* post them in your log, or it will be deleted. You do NOT need to wait for a response from me in order to log.
1) From your own observations, and based on information above, do you feel that this particular set of Petroglyphs have been protected with any type of sealant? Why do you believe this?
2) From your own observations, how many "Cupules" do you count on Sprayberry Rock?
3) From your own observations, how much of the boulder do you estimate is exposed above ground? For example, all of it, only the tip top, half of it, etc.
4) Post a personal picture in your log of your GPS, yourself, a thumbs up, etc at the site . Be careful not to expose answers in the photo.