GUYS YOU NEED TO VOTE FOR CARRACOSTA. KAORI AND I KNOW EVERYTHING SO AGREE WITH US.
...either way, for Carracosta, having access to Shell Smash, good defences in general further boosted by its great ability, and the fact that it has good attack in general too AND the fact that with Swift Swim its speed is suddenly increased! Idk, I see more positives than negatives with this awesome turtle.
As for Archeops, yeah it has flaws battling-wise, but really, if you put a Choice Band on it - and with Wish support it could do pretty good imo. Competitively you COULD mark it work, but it would need a lot of support in order to be any good - actually, even a choice Scarf with maxed attack EVs would do pretty good, imo, since you'd outspeed the opponent, not letting them damage you. BUT Archeops has more weaknesses than Carracosta. :( A flaw is you'd also be Scizor-weak. Actually, Ice Shard weak, too, so kinda weak to priority. :x As well as that, you've also got the fact that it doesn't have many flying STABs that ARE strong. On the plus side it has Stone Edge, but imo, it's pretty much outclassed by Aerodactyl since Aerodactyl doesn't lose power mid-HP, and while it is lower than Archeops' overall base attack, it's actually higher when Archeops power drops without either having a Choice Band - plus faster speed. As a flying fossil type, Archeops is just no good.