Authorities say 15 defendants were among a group that assaulted police officers with their hands and bottles of water.
Authorities say one person who appeared in court Monday was arrested wearing body armor and carrying a loaded handgun and four knives. The Boston Globe reports he pleaded not guilty to a weapons violation.
Police say 33 people were arrested Saturday and four had weapons. Authorities say the protests were mostly peaceful.
One person died in Charlottesville, where a week earlier white supremacists clashed with counterprotesters.